Internet Protocol (IP) Fast Reroute, as described in Request for Comment (RFC) 5286, is a technique for forwarding traffic within a network, without incurring loss during an outage, when there is sufficient redundancy in the network to support alternative paths. More specifically, RFC 5286 describes a technique for using loop-free alternates to provide local protection for traffic, in pure IP networks and in Multiprotocol Label Switching (MPLS) networks using the Label Distribution Protocol (LDP), in the event of a failure condition (e.g., failure of a link, node, or shared risk link group (SRLG).
In many IP networks employing IP Fast Reroute, for example, the IP networks may recover from failures by rerunning a shortest path algorithm while assuming that the failed component does not exist in the IP network, which generally leads to an alternative route via which the IP networks may resume forwarding of the traffic. Disadvantageously, however, rerouting packets via alternate routes within the context of LDP is generally too slow to satisfy customer Quality-of-Service (QoS) expectations for voice and other applications (e.g., the associated recovery/reroute time may exceed several seconds) and, further, packets forwarded to a node associated with a dropped link may be routed in a manner that creates a loop condition that may render a portion of the network unusable.